Reconfigurable circuits have been widely used in the semiconductor industry for field programmable gate arrays (FPGAs) and for repair of a defective memory element. The FPGA consists of a set of simple, configurable logic blocks in an array with interspersed switches that can rearrange the interconnection between the logic blocks.
Reconfigurable circuits are also expected to play a significant role in three-dimensional (3D) integration technology that is presently being developed. Three-dimensional integration fabricates multilayer structures which are vertically stacked one upon another that can form a single chip combination with different functionalities. In these multilayered and multifunctional structures, reconfigurable circuit connection is typically needed to provide controllable logic functionality, memory repair, data encryption as well as other functions.
Phase change material based on programmable vias propose to offer advantages such as, for example, spatial compactness, no need for latches, multiple-shot reprogrammability, and immunity from soft errors, with no significant requirement of high switching voltage or high switching power, both in FGPA and 3D integration applications.
In the prior art, the concept and the device of a programmable via structure and fabricating the same using 3D integration are proposed. Although such proposals have been made, prior art programmable via structures are designed for three-terminal applications and such structures are not good practical use when one intends to switch and control the signal from a separate current source.
In view of the above, there is a continued need for providing new and improved programmable via structures that can be used in applications in which one needs to switch and control the signal from a separate current source. That is, there is a need for a semiconductor structure that includes programmable vias that provide a fast and reliable logic switching medium.